Inter-body implant

ABSTRACT

A system for implanting an inter-body device between adjacent vertebrae comprises an inter-body device having a plurality of cans secured to a flexible bridge and having a relief portion therebetween. An inserter tube and complementary bullnoses are advantageously secured to the vertebrae by an extension arm for securing the assembly precisely in place. A plurality of articulating trial implants are provided to test fit a disc space for the proper sized inter-body device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.14/331,793, filed Jul. 15, 2014, which is a division of U.S. patentapplication Ser. No. 12/833,352, filed Jul. 9, 2010, now U.S. Pat. No.8,828,082, which claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/224,333, filed Jul. 9, 2009, the entire contentsof each of which are incorporated by reference herein.

TECHNICAL FIELD

The present invention relates generally to an inter-body device forintervertebral disc replacement or inter-body spinal fusion and morespecifically to a system including a device for disc replacement or aninter-body device for spinal fusion and an insertion system and methodfor placing the aforementioned devices in an intervertebral spaceutilizing a plurality of surgical approaches.

BACKGROUND

The normal human spine is comprised of seven cervical, twelve thoracic,and five lumbar vertebrae. Intervertebral discs are interposed betweenadjacent vertebrae with the exception of the first two cervicalvertebrae. The spinal vertebrae are supported by ligaments, tendons andmuscles which allow movement such as flexion, extension, lateral bendingand rotation.

Motion between vertebrae occurs through the relative motion of the discand two facet joints. The disc lies in the front or anterior portion ofthe spine. The facet joints lie laterally on either side of theposterior portion of the spine. The basic shape of a humanintervertebral disc is oval, having a depression in a longitudinal sidethereof to form a kidney bean shape.

The spine is a flexible structure that is capable of great curvature andtwist in a plurality of directions. However, developmental or geneticirregularities, trauma, chronic stress and degeneration due to wear mayresult in the need for surgical intervention to effect repair. In casesof degeneration (or injury and disease) it may be necessary or desirableto remove a disc that is no longer performing the function of separationbetween adjacent vertebrae. This is particularly desirable in cases ofdegeneration or herniation, which often result in chronic anddebilitating back pain.

A damaged disc may be replaced with a prosthetic disc that is intendedto be functionally identical to the natural disc. Some prior artreplacement discs are shaped to approximate the shape of the naturaldisc that is being replaced, and further are comprised of a flexiblematerial having a shape memory such that the disc may be deformed forinsertion through a small area in the spine, then expand to its normalshape once insertion is completed. One of the major difficulties withmany prior art discs is that they are most easily inserted utilizing ananterior surgical insertion due to the structure of the spine andarrangement of nerves proximate the spine. The anterior surgicalapproach to disc replacement is, however, quite invasive.

Furthermore, many prior art disc replacements are complex devices madeof a combination of materials and are also bulky and difficult to placeproperly between adjacent vertebrae. The implantation of these prior artdevices requires invasive surgery for proper placement. Additionally,some disc replacements utilize materials such as hydrogels to simulatethe gelatinous texture of the natural disc nucleus. However, thesematerials tend to be easily damaged during implantation and also tend tomigrate into undesired areas of the body.

A number of prior art inter-body devices to effect the fusion ofadjacent vertebrae to each other are also employed to alleviate the painand discomfort caused by disc degeneration. Implantation of these priorart devices is typically quite unwieldy and invasive due primarily totheir complex structure and the complex geometry of the human spine.

Accordingly, a need exists for an inter-body disc device or a discreplacement device and an implantation system for inserting theinter-body fusion or disc replacement device that are robust andsurgically minimally invasive for the efficacious replacement of damagedor degenerated intervertebral discs.

SUMMARY OF THE INVENTION

The present invention obviates the aforementioned difficulties in theprior art by providing an improved inter-body device that more closelyresembles natural disc physiology and by providing a system and methodfor deploying improved inter-body devices that enables a surgeon toaccurately and quickly place an inter-body device of appropriate size ina disc space, thereby minimizing surgery times and greatly enhancingrecovery times for disc replacement surgeries.

The improved inter-body devices of the present invention comprise aplurality of cans, or generally annular bodies, that extend from aflexible bridge that permits the cans to flex independently and compresstogether for ease of deployment in said disc space, while relaxing totheir natural shape once deployed. The cans may further include aplurality of apertures for accepting bone graft material to aid in thefusion process, as well as corrugated upper and lower surfaces that actto guide the inter-body devices upon entry into the disc space andengage the adjacent vertebrae.

The inter-body insertion system of the present invention includes aninserter tube that is shaped to guide a plurality of instruments intothe disc space in the same orientation throughout the process. Onceinserted, the inserter tube may be secured to the spine by means of anextension arm that locks the tube in place. A plurality of bullnoseinstruments having distal tips of varying shapes are used to prepare thedisc space for entry of the inter-body device as well as to aid ininserting the inter-body device into the disc space.

Additionally, the system of the present invention includes a pluralityof articulating trial implants that may be inserted to determine theproper implant length prior to deployment of an inter-body device. Thetrial implants of the invention may articulate with respect to animplant rod that aids in positioning them in the disc space, therebyproviding for relatively easy trial implant insertion and removal.

The invention further comprises a novel inserter tube handle that iscapable of being secured to a complementary handle that attaches to aplurality of bullnose instruments for insertion into the disc space. Abox cutter having a distal tip with opposed cutting edges is provided toshave the posterior endplates of adjacent vertebrae in preparation forimplant insertion.

The invention also includes a bone graft insertion system that utilizesa novel bone graft plunger for distributing morselized bone graftmaterial throughout the anterior disc space.

Other features, advantages, and objects of the present invention willbecome apparent from the detailed description of the invention hereinbelow, taken in conjunction with the appended drawing Figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a perspective view of a an inter-body device and an insertertube in accordance with one embodiment of the present invention;

FIG. 2 is a perspective view of a an inter-body device and an insertertube in accordance with one embodiment of the present invention;

FIG. 3 is a perspective view of a an inter-body device and an insertertube in accordance with one embodiment of the present invention;

FIG. 4 is a top view of an inter-body device in accordance with oneembodiment of the present invention;

FIG. 5 is a top view of an inter-body device in accordance with oneembodiment of the present invention;

FIG. 6 is a top view of an inter-body device in accordance with oneembodiment of the present invention.

FIG. 7 is a top view of an inter-body device in accordance with oneembodiment of the present invention;

FIG. 8 is a top view of an inter-body device in accordance with oneembodiment of the present invention;

FIG. 9 is a perspective view of an inter-body device in accordance withone embodiment of the present invention;

FIG. 10 is a perspective view of an inter-body device in accordance withone embodiment of the present invention;

FIG. 11 is a top view of an inter-body device in accordance with oneembodiment of the present invention;

FIG. 12 is a top view of an inter-body device in accordance with oneembodiment of the present invention;

FIG. 13 is a top view of an inter-body device in accordance with oneembodiment of the present invention;

FIG. 14 is a perspective view of an inter-body device in accordance withone embodiment of the present invention;

FIG. 15 is a perspective view of an inter-body device in accordance withone embodiment of the present invention;

FIG. 16 is a perspective view of an inter-body device in accordance withone embodiment of the present invention;

FIG. 17 is top view of an inter-body device in accordance with oneembodiment of the present invention;

FIG. 18 is a top view of an inter-body device in accordance with oneembodiment of the present invention;

FIG. 19 is a top view of an inter-body device being advanced into a discspace in accordance with one embodiment of the present invention;

FIG. 20 is a perspective view of an inter-body device push rod inaccordance with one embodiment of the present invention;

FIG. 21 is a perspective view of an insertion tool in accordance withone embodiment of the present invention;

FIG. 22 is an exploded view of an insertion tool in accordance with oneembodiment of the present invention;

FIG. 23 is a perspective view of a trial implant in accordance with oneembodiment of the present invention;

FIG. 24 is a perspective view of a bullnose and trial handle inaccordance with one embodiment of the present invention;

FIG. 25 is a partial view of a bullnose and inserter in accordance withone embodiment of the present invention;

FIG. 26 is a perspective view of a trial implant in accordance with oneembodiment of the present invention;

FIG. 27 is a partial view of a bullnose and inserter in accordance withone embodiment of the present invention;

FIG. 28 is an exploded view of a bullnose and trial handle in accordancewith one embodiment of the present invention;

FIG. 29 is a perspective view of an assembled bullnose and trial handlein an inserter tube in accordance with one embodiment of the presentinvention;

FIG. 30 is a side view of an inserter tube in accordance with oneembodiment of the present invention;

FIG. 31 is a side view of an inserter tube in accordance with oneembodiment of the present invention;

FIG. 32 is a perspective view of a trial implant and trial handle inaccordance with one embodiment of the present invention;

FIG. 33 is a side view of a trial implant in accordance with oneembodiment of the present invention;

FIG. 34 is a perspective view of a trial handle in accordance with oneembodiment of the present invention;

FIG. 35 is an exploded view of a trial handle in accordance with oneembodiment of the present invention;

FIG. 36 is a perspective view of a trial implant and implant rod inaccordance with one embodiment of the present invention;

FIG. 37 is a perspective view of a trial implant in accordance with oneembodiment of the present invention;

FIG. 38 is a top view of an inserter tube and trial implant advancinginto a disc space in accordance with one embodiment of the presentinvention;

FIG. 39 is a top view of an inserter tube and trial implant advancinginto a disc space in accordance with one embodiment of the presentinvention;

FIG. 40 is a top view of an inserter tube and trial implant advancinginto a disc space in accordance with one embodiment of the presentinvention;

FIG. 41 is a top view of an inserter tube and trial implant advancinginto a disc space in accordance with one embodiment of the presentinvention;

FIG. 42 is a top view of an inserter tube and trial implant advancinginto a disc space in accordance with one embodiment of the presentinvention;

FIG. 43 is a top view of an inserter tube and trial implant advancinginto a disc space in accordance with one embodiment of the presentinvention;

FIG. 44 is a partial side view of an inter-body device and bullnoseinside an inserter tube in accordance with one embodiment of the presentinvention;

FIG. 45 is a partial side view of an inter-body device and bullnoseinside an inserter tube in accordance with one embodiment of the presentinvention;

FIG. 46 is a partial top view of a bullnose in accordance with oneembodiment of the present invention;

FIG. 47 is a partial bottom view of a bullnose in accordance with oneembodiment of the present invention;

FIG. 48 is a partial top view of a bullnose in accordance with oneembodiment of the present invention;

FIG. 49 is a partial bottom view of a bullnose in accordance with oneembodiment of the present invention;

FIG. 50 is a top view of an inserter tube in a disc space, with aninter-body device and bullnose advancing into said disc space inaccordance with one embodiment of the present invention;

FIG. 51 is a top view of an inserter tube in a disc space, with aninter-body device and bullnose advancing into said disc space inaccordance with one embodiment of the present invention;

FIG. 52 is a top view of an inserter tube in a disc space, with aninter-body device and bullnose advancing into said disc space inaccordance with one embodiment of the present invention;

FIG. 53 is a perspective view of a box cutter in accordance with oneembodiment of the present invention;

FIG. 54 is a side view of a box cutter in accordance with one embodimentof the present invention;

FIG. 55 is a side view of an inserter tube advanced into a disc space inaccordance with one embodiment of the present invention;

FIG. 56 is a perspective view of a trial handle and a bullnose inaccordance with one embodiment of the present invention;

FIG. 57 is a perspective view of a trial handle and a bullnose inaccordance with one embodiment of the present invention;

FIG. 58 is a cross-sectional side view of a bullnose and inter-bodydevice being advanced through an inserter tube in accordance with oneembodiment of the present invention;

FIG. 59 is a perspective view of an inter-body device insertion tool inaccordance with one embodiment of the present invention;

FIG. 60 is a perspective view of an inter-body device insertion tool inaccordance with one embodiment of the present invention;

FIG. 61 is a perspective view of a bone graft funnel secured to aninserter tube in accordance with one embodiment of the presentinvention;

FIG. 62 is a perspective view of a bone graft funnel in accordance withone embodiment of the present invention;

FIG. 63 is a perspective view of a bone graft funnel in accordance withone embodiment of the present invention;

FIG. 64 is an exploded perspective view of a bone graft plunger inaccordance with one embodiment of the present invention;

FIG. 65 is a perspective view of a bone graft plunger in accordance withone embodiment of the present invention;

FIG. 66 is a perspective view of a bone graft plunger in accordance withone embodiment of the present invention;

FIG. 67 is a side view of a bone graft plunger in accordance with oneembodiment of the present invention;

FIG. 68 is a perspective view of a bone graft plunger in accordance withone embodiment of the present invention;

FIG. 69 is a cross-sectional side view of a bone graft plunger beingadvanced through an inserter tube into a disc space in accordance withone embodiment of the present invention;

FIG. 70 is a side view of a bone graft plunger being advanced through aninserter tube into a disc space in accordance with one embodiment of thepresent invention;

FIG. 71 is a cross-sectional side view of a bone graft plunger beingadvanced through an inserter tube in accordance with one embodiment ofthe present invention;

FIG. 72 is a perspective view of an extension arm in accordance with oneembodiment of the present invention;

FIG. 73 is a side view of an extension arm in accordance with oneembodiment of the present invention;

FIG. 74 is a perspective view of an extension arm in accordance with oneembodiment of the present invention;

FIG. 75 is a perspective view of an extension arm in accordance with oneembodiment of the present invention;

FIG. 76 is a perspective view of an extension arm in accordance with oneembodiment of the present invention;

FIG. 77 is a perspective view of an extension arm in accordance with oneembodiment of the present invention;

FIG. 78 is a perspective view of an extension arm in accordance with oneembodiment of the present invention;

FIG. 79 is a perspective view of an extension arm in accordance with oneembodiment of the present invention;

FIG. 80 is a perspective view of the system of the present invention inplace in the environment of a human spine in accordance with oneembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to the drawing Figures, and in particular FIGS. 1-3, andin accordance with a preferred constructed embodiment of the system 10of the present invention, there is depicted an inter-body device 20 andan inserter tube 100 for orienting and inserting said inter-body device20 into a disc space of a human spine. Drawing FIGS. 50 and 55 depictone example of the insertion of inter-body device 20 into a disc space 2of a spine 1 between vertebrae 4, and may be referred to throughout thisspecification for reference to the human anatomy to which the presentinvention is applied. Furthermore, it should be noted that the disc tobe replaced by the inter-body device 20 of the present invention isfirst removed by a surgeon performing a thorough discectomy. Typically,it is desirable to extend the discectomy to a contralateral half of thedisc space to allow placement of the longest inter-body device 20possible and to maximize bony surface exposure for fusion to occur. Ifthere is significant disc space 2 collapse, a complete discectomy maynot be possible until disc space 2 distraction is performed utilizingone of many known in the art distraction tools.

As seen in FIG. 1, inter-body device 20 may comprise a plurality oflobes or cans 30, each spaced one from another and depending from aflexible bridge 60 that permits independent flexure and motion of eachcan 30 to facilitate entry into disc space 2. Flexible bridge 60 may becomprised of a memory metal such as nitinol or other flexible plasticmaterial that has shape memory so that the overall shape of inter-bodydevice 20 is retained once device 20 is implanted. In the embodiments ofthe invention depicted in FIGS. 1-3 each can 30 includes a pair ofgenerally parallel passageways 32 therein, through which a suture 3 maybe threaded to aid in positioning of inter-body device 20, as well as toenable retrieval device 20 should its' placement prove unsatisfactory.Once inter-body device 20 is properly inserted into disc space 2, suture3 may be manipulated to aid in implant positioning by pulling on eitherend thereof. Once device 20 is properly positioned, suture 3 may simplybe pulled through both passageways 32 and thus removed from inter-bodydevice 20.

Inter-body device 20 cans 30 may further comprise an upper surface 34and a lower surface 36 that contact upper and lower surfaces of adjacentvertebrae 4 once inter-body device 20 is properly positioned in discspace 2. Inter-body device 20 may further comprise an anterior wall 40that may be integral with bridge 60, and may be generally convex inshape. Anterior wall 40 may terminate in distal and proximal cans 30.Anterior wall 40 includes an interior wall portion 42 that extendsbetween adjacent cans 30. Additionally, each can 30 includes a posteriorwall 44 that extends generally between upper 34 and lower 36 portions ofcans 30 on a posterior portion thereof.

While many embodiments of the inter-body device 20 of the presentinvention are shown to have a generally anterior curvature, it should berecognized that inter-body devices 20 having a posterior curvature arewithin the scope of the present invention. Additionally, inter-bodydevice 20 is preferably formed of a material that is durable andnon-reactive. A wide variety of biocompatible materials may be utilizedto manufacture the inter-body device 20 of the present invention,including but not limited to biocompatible polymers, elastomericmaterials, hydrogels, hydrophilic polymers, shape memory polymers, andshape memory metals. It is understood that one of ordinary skill in theart would be aware of a variety of materials suitable for suchimplantation. In one embodiment of the invention, inter-body device 20is comprised of a carbon fiber material while in another, device 20 iscomprised of a polyetherketone (PEK) material.

As shown in FIG. 1, proximal can 30 may include a hitch 50, depicted inthis embodiment of the invention as a generally annular protrusionextending outwardly from proximal can 30, which may be grasped orsecured to various insertion tools as will be discussed in greaterdetail herein below.

FIGS. 1-3 also depict an inserter tube 100 shown with one wall removedto show the path of suture 3 through inserter tube 100. Inserter tube100 comprises a pair of opposed upper and lower walls 102, 104 andopposed medial and lateral walls 106, 108 that define a hollow tubularmember through which inter-body device 20 may be deployed. Inserter tube100 includes a distal end 110 wherein lateral wall 108 forms a curvedportion 112 that guides the deployment of inter-body device 20 as it isadvanced through inserter tube 100. In this embodiment of the presentinvention lateral wall 108 curved portion 112 has a length greater thanthat of medial wall 106 to allow inter-body device 20 to curve into discspace 2 as it is advanced through inserter tube 100.

Cans 30 of each inter-body device 20 are spaced such that a relief area38 is defined by the void space between cans 30. Relief area 38 permitsinter-body device 20 and cans 30 to flex and compress during insertionand placement into disc space 2 while returning to its relaxed shapeonce it is properly positioned. FIG. 2 depicts an inter-body device 20having only two cans 30, thereby providing for a much larger relief area38. FIG. 3 depicts an inter-body device 20 wherein suture 3 is knottedat a terminal end for retrieval of device 20 back through inserter tube100.

FIG. 4 is a top view of an embodiment of the present invention wherebyeach can 30 of inter-body device 20 includes an aperture 46 therein foraccepting a morselized bone graft material to enhance the spinal fusionprocess. Additionally, as seen in FIG. 4 hitch 50 may comprise agenerally annular aperture 52 therein for accepting a pin (not shown) orother instrument for inserting, retrieving and positioning inter-bodydevice 20 in disc space 2.

FIGS. 5 and 6 depict a further embodiment of the present inventionwhereby relief portion 38 of inter-body device 20 proximate interiorwall 42 defines an elongated slot that enables bridge 60 to flex whileeach can 30 flexes independently of the other and is capable of motionin three planes. This feature of the invention enables accuratepositioning of device 20 in disc space 2 by allowing device 20 to deformduring insertion into disc space 2 and expand back to its relaxed shapeonce properly inserted. The embodiment of the invention shown in FIG. 5depicts upper surfaces 32 having a plurality of corrugated ridges 33thereon. Lower surfaces 34 may also include a plurality of corrugatedridges 33 to allow inter-body device 20 to engage the upper and lowersurfaces of adjacent vertebrae when inserted in disc space 2, which alsoassists in device 20 positioning within disc space 2.

FIG. 7 depicts a yet further embodiment of inter-body device 20 wherebyflexible bridge 60 is secured to a pair of opposed cans 30, the proximalone of which includes a hitch 50 depending therefrom to facilitateinsertion and removal. FIG. 8 depicts a similar embodiment to that ofFIG. 7 wherein flexible bridge 60 extends around can 30 posterior wall44 to firmly secure can 30 to bridge 60 while still permittingindependent movement of each can 30.

FIG. 9 shows an additional exemplary embodiment of inter-body device 20having a pair of spaced opposed flexible bridges 60, each secured to apair of spaced cans 30 providing a relatively large relief area 38. Inthis embodiment of the invention, a hitch 50 is provided having a pairof spaced flanges 54 extending from proximal can 30, each with anaperture 52 therein to accept a pin (not shown) for connectinginter-body device 20 to an insertion and removal tool as will bediscussed in greater detail herein below.

Referring now to FIGS. 10-14 there are depicted a plurality ofarticulating inter-body devices 200 in accordance with a yet furtherembodiment of the present invention. Inter-body device 200 comprises adistal half 210 and a proximal half 220 connected by a central hinge230. Each half 210, 220 of trial implant 200 includes a passageway 232into which a segment of flexible spine 240 is inserted. Flexible spine240 may be comprised of a memory metal to permit halves 210, 200 to flexwith respect to each other then return to a relaxed position. A hitch 50is also provided extending from proximal half 220 of trial implant 200to facilitate insertion and removal thereof form disc space 2.

FIGS. 10 and 11 depict central hinge 230 disposed approximately in thecenter of distal and proximal halves 210, 220, while FIG. 12 depictshinge 230 disposed on the anterior edges of distal and proximal halves210, 220 to permit flexure in the anterior direction. FIG. 13 depictshinge 230 disposed on the posterior edges of distal and proximal halves210, 220 to permit flexure in the posterior direction. Finally, FIG. 14depicts a further embodiment of the invention having a plurality ofapertures 234 therein to accept bone graft material to aid in vertebralfusion.

It should be noted that the embodiments of inter-body device 20 depictedin FIGS. 10-14 may also be employed as trial implants, whereby they areinserted into disc space 2 prior to insertion of a permanent implant totest fit disc space 2 for proper size and positioning, and to determinethat disc space 2 is properly prepared to receive inter-body device 20.Where inter-body devices 20 are employed as trials, they may bemanufactured of a suitable material capable of reuse after propersterilization, as is well known in the surgical arts.

Referring now to FIGS. 15-17, an exemplary embodiment of inter-bodydevice 20 is shown formed of a single piece of material, wherebyflexible bridge 60 is integral with a pair of spaced elongated cans 30,each having upper 34 and lower 36 surfaces with an aperture 46 thereinfor accepting bone graft material. The embodiment of the presentinvention depicted in FIGS. 15 and 17 further comprises a plurality ofridges 33 on upper 34 and lower 36 surfaces to facilitate vertebralengagement of device 20. Additionally, in this embodiment of theinvention a portion of one can 30 comprises a void or slot 56 therein,that extends around an end of said can 30 and into posterior wall 44thereof. Additionally, a pair of opposed apertures 58 communicate withslot 56 to accept a pin 59 that is secured in apertures 58. Pin 59 canthen easily be accessed by an insertion and removal tool as discussedbelow.

Furthermore, in this embodiment of the invention flexible bridge 60extends outwardly towards the distal and proximal ends, respectively, ofcans 30 to define a relief area 38 that permits considerable flexure andstraightening of device 20 as it is deployed through inserter tube 100.In a yet further embodiment of the invention, distal can 30 may comprisea beveled distal edge portion 31, best seen in FIGS. 15 and 16, thatfacilitates smooth entry of device 20 into disc space 2 since the heightof distal can 30 is slightly less than the height of inter-body device20 along the remainder of its length.

It is to be understood from the teachings of this specification that theembodiments of inter-body device 20 shown and described herein may beproduced in a wide variety of sizes, varying in both overall length andheight, as well as varying in spacing between cans 30 and bridge 60 suchthat the invention may be adapted for use in nearly any size disc spaceas required by a surgeon. Furthermore, it is to be understood that theinter-body devices 20 described herein may include a plurality ofradiographic markers disposed at a plurality of points in or on saidinter-body devices 20, to enable a surgeon to ensure proper placement ofsaid devices 20 by conventional radiographic techniques.

Referring now to FIG. 19 there is shown a flexible implant guide sleeve140 that is sized to be inserted through inserter tube 100 into discspace 2. In this embodiment of the invention inter-body device 20 iscarried by a distal end 142 of guide sleeve 140 until it is properlypositioned in disc space 2 then guide sleeve 140 is retracted back intoinserter tube 100. Guide sleeve 140 may advantageously be formed of athin memory metal or equivalent flexible material capable of curvinginto disc space 2. Furthermore, in one embodiment of the invention therelaxed shape of guide sleeve 140 distal end 142 approximates that ofinter-body device 20 and disc space 2 to facilitate placement of device20 therein.

FIG. 20 depicts an inter-body device push rod 160 adapted to be insertedinto the interior of inserter tube 100, having a clasp 162 at a distalend 164 thereof. Clasp 162 may be actuated by known-in-the art means toengage and release a pin 59 of an inter-body device 20, for example thedevice 20 depicted in FIG. 15. Distal end 164 of push rod 160 may besized to fit into slot 56 of inter-body device 20, thereby enablingdevice 20 to rotate into disc space 2 before being release bydisengagement of clasp 162.

Referring now to FIGS. 21 and 22, there is depicted an alternativeinter-body insertion tool 300 in accordance with one embodiment of thepresent invention. Insertion tool 300 comprises an elongated centralbody 310 having a handle 312 secured thereto and extending upwardlytherefrom, and a lock button 314 that is inserted through an aperture316 in an upper surface of central body 310. Central body 310 furtherincludes a channel 318 that extends longitudinally through central body310, shaped to accept an elongated shaft 320 having a clasp 322 at adistal end 324 thereof for engaging an inter-body device 20. Shaft 320further comprises a pair of spaced apertures 326 therethrough that alignwith a complementary pair of spaced apertures 330 in central body 310,and into which a pair of locking pins 328 are inserted to secure shaft320 into central body 310.

Insertion tool 300 further comprises a stationary member 340 thatincludes a handle 342 secured thereto and extending outwardly therefrom,and an elongated slot 344 that is shaped to engage elongated centralbody 310. Stationary member 340 comprises a distal tip 346 shaped todirect an inter-body device 20 into a disc space, as well as anelongated groove 348 in a portion thereof. Central body 310 fits closelyinto slot 344 of stationary member 340, and is slidable therein toenable central body 310 to be advanced forward such that clasp 22extends into disc space 2 to position inter-body device 2.

Insertion tool 300 further comprises a sliding member 360, having ahandle 362 extending therefrom and including a tongue 364 extendinglongitudinally on a portion of sliding member 360 that engages groove348 of stationary member 340. Sliding member 360 further comprises adistal tip 366 that is generally flat. When assembled, and as best seenin FIG. 21, sliding member 360 and stationary member 340 form a channelinto which an inter-body device 20 may be inserted, secured by clasp 322of central body 310 shaft 220. Sliding member 360 is capable of movingforward relative to stationary member 340, thereby enabling distal tip366 to enter and distract disc space 2 to facilitate device 20 delivery.Once so inserted, stationary member 340 and central body 310 are alsoinserted into disc space 2 for delivery of inter-body device 20. Thisfeature of the instant invention provides an insertion tool 300 thatassists in disc space distraction for ease of implant insertion.

Referring now to FIGS. 23, 32, 33, 36, and 37 the present inventionfurther comprises a trial implant 400 for determining the proper size ofa permanent inter-body device 20 to be deployed, having a distal end 402and a proximal end 404 secured together via a central hinge 406 thatenables ends 402, 404 to rotate in a single plane relative to eachother. Trial implant 400 is shaped to generally conform to the shape ofinter-body device 20 that will be deployed for permanent use in discspace 2. Proximal end 404 of trial implant 400 includes a slot 408therein, and a pin 410 secured transversely to slot 408 for securingtrial implant 400 in an articulating fashion to a trial implant rod 420.

Trial implant rod 420 comprises an elongated body 421 terminating in apair of spaced distal tips 422 that abut trial implant 400 at theirdistal ends. Trial implant rod further comprises a pin hinge 424 thatextends through and is secured to both spaced distal tips 422 and aproximal end 426 having a threaded aperture therein for engagement witha trial implant insertion tool. An articulating arm 430 having anaperture at a distal end 432 thereof is rotatably secured to pin 410 oftrial implant 400. Articulating arm 430 further comprises a proximal end434 having a slot 436 therein that is engaged by hinge pin 424 ofimplant rod 420 so that articulating arm 430 is capable of bothrotational and longitudinal movement with respect to implant rod 420.Furthermore, since trial implant 400 rotates around pin 410, bothimplant 400 and articulating arm 430 are capable of rotational motionwith respect to implant rod 420.

FIG. 32 depicts trial implant 400 and implant rod 420 secured to aninsertion tool 500 having a trial handle 510 secured to a threaded shaft502. It should be noted that trial handle 510 is designed to connect toa plurality of components of the present invention, as will be discussedfurther herein below. FIG. 36 depicts an alternative embodiment of trialimplant rod 420 wherein distal tips 422 include hinge 424 at a distalportion thereof such that articulating arm 430 extends outwardly towardtrial implant 400. As seen in FIG. 37 trial implants 400 may furtherinclude a flexible spine 412 inside distal and proximal ends 402, 404,similar to those embodiments shown in FIGS. 10-14.

FIG. 24 depicts a trial handle 510 secured to a bullnose 600 designed toaid in distraction of disc space 2 as well as insertion of inter-bodydevices 20 therein. Bullnose 600 comprises an elongated shaft 602capable of engaging and being secured to handle 510 at a proximal end604 thereof, and a distal end 606 having a tapered distal tip 610thereon, for inserting into and distracting disc space 2. FIG. 25depicts bullnose 600 distal tip 610 exiting distal end 110 of insertertube 100.

FIGS. 26-29 depict an alternative embodiment of bullnose 600 utilizedfor inter-body device 20 insertion having a blunt distal tip 610 atdistal end 606. Shaft 602 includes a suture 3 guide groove 612 along asubstantial portion thereof that terminates in a wide groove end 614proximate distal end 606 of bullnose 600. Guide groove 612 provides aspace in which suture 3 is disposed when bullnose 600 is insertedthrough inserter tube 100, as shown in FIG. 29. Bullnose 600 proximalend 604 further includes an annular groove 616 that is engaged by alatch (such as a pin or spring-loaded ball, not shown) interior tohandle 510. In operation, suture 3 may be secured to inter-body device20 as shown in FIGS. 1-3 and may ride in groove 612 of bullnose 600 asit is advanced through inserter tube 100 into disc space 2.

Referring again to FIG. 28 and to FIGS. 34 and 35, trial handle 510 isshown in further detail. Handle 510 includes a distal end 512 having anaperture 514 therein for engaging a proximal end 604 of bullnose 600. Alocking flange 520 is also disposed on distal end 512 of handle 510 forengaging a complementary flange of, for example, inserter tube 100.Handle 510 may also include lock 524 and unlock 522 marks on an exteriorsurface thereof indicating that inserter tube 100 is locked onto handle512 when a corresponding mark on tube 100 is aligned with lock mark 524,and alternatively unlocked with a corresponding mark on tube 100 isaligned with unlock mark 522. Handle 522 may include a release button530 that is biased by spring 532 to engage (or disengage) a locking pin516 extending through the distal end 512 thereof, for releasing bullnose600 from engagement with handle 510.

FIGS. 29-31 depict one exemplary embodiment of inserter tube 100 and itsengagement with handle 510. Inserter tube 100 includes a distal end 100terminating in a curved portion 112 and a proximal end 114 terminatingin a hollow handle 120 that communicates with tube 100, said handle 120having a locking flange 122 on an interior circumference thereof thatengages complementary locking flange 520 of trial handle 510. Insertertube 100 handle 120 may also include an alignment arrow 124 that, whenaligned with one of the lock/unlock markings 524, 522 of handle 510indicate that locking flange 122 of inserter tube 100 is engaged ordisengaged with locking flange 520 of handle 110. In a furtherembodiment of the invention, inserter tube handle 120 may comprise asmall groove in a proximal edge thereof to accommodate suture 3 as itexits handle 120 when inter-body device 20 is being deployed.

FIG. 29 additionally shows bullnose 600 inserted into inserter tube 100and extending through distal end 110 thereof. As can be seen from thisdrawing Figure, bullnose 600 may be secured to handle 510 thenceinserted into inserter tube 100, which is then locked onto handle 510.By carefully positioning inserter tube 100 into disc space 100, bullnose600 may then be inserted to an exact depth into disc space 2 necessaryfor suitable placement of inter-body device 2. Accordingly, insertertube 100 may be provided with a plurality of depth markings along theexterior surfaces thereof (for example on upper and lower walls 102, 104and on medial and lateral walls 106,108) to assist a surgeon in properplacement of inserter tube 100, as will be discussed in further detailherein below.

FIGS. 38-43 depict the deployment of trial implant 400 through insertertube 100 into disc space 2. Firstly, inserter tube 100 and concomitantbullnose 600 are inserted into disc space 2 through an annulotomy as farlaterally in the disc space as possible. This first step is typicallypracticed with bullnose 600 having a tapered tip 610 to aid in discspace distraction. In one embodiment of the present invention, thetapered tip 610 extends approximately 15 mm past beyond the distal end110 curved tip 112 of inserter tube 100. A surgeon may note the depth ofthe inserter tube in the annulotomy at this stage of the procedure.

Secondly, a blunt tip 610 bullnose is assembled to trail handle 510 andinserter tube 100 and reinserted in disc space 2 In one embodiment ofthe present invention, the blunt tip 610 extends approximately 10 mmpast beyond the distal end 110 curved tip 112 of inserter tube 100. Theblunt tip 610 and concomitant inserter tube 100 are advanced into discspace 2 until distal tip 610 of bullnose 600 touches the anteriorannulus 5 of disc space 2. At this point, bullnose 600 may be withdrawnand inserter tube 100 locked into place, as will be discussed furtherherein below.

A trial implant 400 is now secured to trial handle 510 and is advancedinto disc space 2, as shown sequentially in FIGS. 38-43. The ability oftrial implant 400 to articulate coupled with the curved portion 112 ofinserter tube 100 enable accurate and easy placement of trial implant400 in disc space 2. Furthermore, differing lengths and heights of trialimplants 400 may be employed to determine the proper size inter-bodydevice 20 to be used. The longest trial implant 400 that can besuccessfully deployed in disc space 2 will determine the length ofinter-body device 20 to be used. Typically, the height of a distractorused to distract the disc space will determine the height of theinter-body device 20 to be deployed.

Referring now to FIGS. 44, 46 and 47, an exemplary deployment ofinter-body device 20 through inserter tube 100 utilizing suture 3 tosecure device 20. In this embodiment of the invention, bullnose 600comprises a single longitudinal suture guide groove 612 and wide grooveend on one side of bullnose 600. FIG. 44 depicts distal tip 610advancing device 20 through inserter tube 100 until it is properlypositioned in disc space 2.

In contradistinction, FIGS. 45, 48 and 49 depict a bullnose 600 having alongitudinal suture guide groove 612 and wide groove end on two sides ofbullnose 600, whereby suture 3 is routed both above and below bullnose600 shaft 602, as best seen in FIG. 45. This embodiment of the inventionfacilitates manipulation and placement of inter-body device 20 in discspace 2.

Referring now to FIGS. 50-52, there is depicted the deployment ofinter-body device 2 through inserter tube 100 into disc space 2.Apertures 46 of cans 30 may be filled with morselized bone graftmaterial prior to inserting inter-body device 20 into inserter tube 100.A suture 3 is secured to hitch 50 of device 20 prior to insertion ininserter tube 100 as well. The suture guide groove 612 of bullnose 600may also be aligned with the groove in inserter tube handle 120 toprovide clearance for suture 3. The looped suture 3 shown in FIGS. 50-52is disposed in groove 612 and bullnose 600 is then inserted intoinserter tube 100, pushing inter-body device 20 into place as itadvances into tube. It should be noted that blunt distal tip 610bullnose 600 is used for insertion of inter-body device 20. Onceproperly positioned, radiographical techniques may be used to verify thepositioning of inter-body device 20, whereupon suture 3 is removed, asis bullnose 600 and concomitant handle 510. Inserter tube 100 may remainin place in disc space 2 for application of bone graft material asdescribed below.

FIGS. 53 and 54 depict a box cutter 300 used to shave posteriorendplates of adjacent vertebrae 4 in preparation for inter-body device20 deployment. Box cutter 700 comprises a central shaft 702 secured to ahandle 704 at a proximal end thereof. Handle 704 may have an option slaphammer flange 706 at a proximal end thereof for attaching a known-in-theart slap-hammer device to aid in use of box cutter 700. A detachablehead 708 is secured to shaft 702 at a distal end thereof, having atapered distal tip 710 to facilitate distraction as head 708 enters thedisc space 2. Head 708 may be provided in varying widths and heights toaccommodate variable spinal geometry, and further may be provided withdepth markers (not shown) along the exterior surfaces thereof to enablea surgeon to determine how far distal tip 710 advances into disc space2. In one embodiment of the present invention box cutter head 708 heightmay be provided by a marking on the surface thereof. Additionally, boxcutter head 708 may include exterior markings indicating the distancefrom distal tip 710.

Box cutter 700 further comprises a pair of spaced cutting edges 714 thatfacilitate the shaving of the posterior endplates with box cutter 700.In operation, box cutter 700 head 708 is selected having an appropriatewidth for a given application, and the posterior endplates of adjacentvertebrae 4 are shaved by advancing cutting edges 714 into disc space 2,utilizing a slap-hammer attachment if necessary.

FIGS. 55-58 depict an alternative embodiment of the inserter tube 100 ofthe instant invention wherein the proximal end 114 is slightly widerthan distal end 110 and wherein no handle is present. FIG. 56 depicts analternative embodiment of bullnose 600 having a proximal end 604 thatincludes a threaded shaft 618 for engaging a handle 510, as well as athreaded stop 620 that is rotatable along threaded shaft 618 that abutsdistal end 114 of inserter tube 100 when bullnose 600 is insertedtherein. FIG. 56 further depicts a conventional “slap-hammer” 6 devicesecured to handle 510 to apply additional longitudinal force to bullnose600 where necessary.

FIG. 57 is a view of bullnose 600 from the opposite side as FIG. 56,depicting a second suture guide groove 612 extending longitudinally intodistal tip 610 of bullnose 600 for positive placement of suture 3. FIG.58 is a cross-sectional view of bullnose 600 deploying inter-body device20 through inserter tube 100, wherein suture 3 is guided in grooves 112both above and below bullnose 600, as suture 3 loops through hitch 50 ofinter-body device 20. This feature of the invention further aids inpositioning of implants as they are deployed into disc space 20.

FIGS. 59 and 60 depict two inter-body device 20 insertion and retrievaltools 750, each having a distal end 752 having a pair of spacedfurcations 754 extending therefrom to engage pin 59 of inter-body device20, or a similar hitch 50. In the embodiment of FIG. 59, furcations 754are spaced to snap-fit onto pin 59 of hitch 50. In the retrieval toolembodiment shown in FIG. 60, a longitudinally slidable sleeve 756 isprovided over distal end 752 of tool 750 that forces furcations 754together to grasp pin 59 as sleeve 756 is advanced toward distal end752.

FIGS. 61 and 62 depict a bone graft funnel 800 that is operativelysecured to inserter tube 100 handle 100 having an aperture 802 thereinfor supplying bone graft material through inserter tube 100 to discspace 2, as well as a flat edge 804 for ease of use, therebyfacilitating use of bone graft funnel with other instruments orstructures employed in spinal surgery. As best seen in FIG. 63, and inan alternative embodiment of bone graft funnel 800, a locking flange 806is provided on one edge thereof for engaging a complementary flange oninserter tube 100 handle 120.

FIG. 64 depicts a bone graft plunger 820 designed for use with bonegraft funnel 800 and inserter tube 100, having an angled plunger tip 822on a distal end thereof. Angled plunger tip 822 may be formed of, forexample, a flexible material such as a silastic elastomer that enablesplunger tip 822 to flex as it extends through inserter tube 100. In oneembodiment of the present invention plunger tip 822 is disposable aftereach use. Furthermore, and in accordance with one embodiment of theinvention, angled tip 822 is sized to be slightly larger than theinterior profile of inserter tube 100 to tightly engage inserter tube100 and enable angled tip 822 to force all the bone graft materialdeposited in inserter tube 100 into disc space 2. Bone graft plunger 820further comprises a central shaft 824 having a distal end 826 that isshaped to snap-fit onto a complementary aperture 828 of angled tip 822,thereby securing tip 822 to shaft 824. A proximal end 830 of shaft 824may include a threaded aperture 832 for securing bone graft plunger to ahandle 510. While plunger tip 822 is be comprised of an elastomericmaterial, making it both flexible and disposable after use, plungershaft 824 may be comprised of elastomer, but may also be produced frommore durable alloys for repeated use after sterilization.

FIG. 66 depicts an alternative embodiment of bone graft plunger 820 thatincludes an elongated angled flexible tip 822 (shown in its relaxedstate) that is secured to a plunger shaft 824. This embodiment of theinvention enables bone graft material to be deposited further into discspace 2 since plunger 820 assumes a relaxed shape that approximates thatof anterior disc space 2.

FIGS. 67 and 68 show an alternative bone graft plunger 820 that is asingle-piece plunger having an integral angled tip 822 and plunger shaft824. Bone graft plunger 820 angled tip 822 may include a curved surface823 designed to push bone graft material through complementary curvedportion 112 of inserter tube 100. Plungers 820 constructed in accordancewith this embodiment of the present invention can be manufactured of anelastomer or metal alloy without departing from the scope of the presentinvention.

FIG. 69 is a cross-section of bone graft funnel 800, plunger 820, andinserter tube 100 in operation. Funnel 800 is secured to inserter tube100 handle 120 and provides a convenient mechanism for depositing bonegraft material 7 into inserter tube 100. Plunger 820 is then insertedinto aperture 802, and through handle 120 into inserter tube 100,thereby forcing all bone graft material 7 deposited therein intoinserter tube 100 and disc space 2. Funnel 800 is then removed fromhandle 120 and plunger 820 is once again used to force the remainingbone graft material in inserter tube 100 into disc space 2. Flexibleangled tip 822 enables plunger 820 to curve into disc space 2 as it isadvanced, thereby providing superior delivery of bone graft material 7.

FIGS. 70 and 71 depict an alternative embodiment of bone graft plunger820, wherein angled tip 822 and shaft 824 are comprised of a singlepiece of memory metal that is curved to approximate the curvature of ananterior portion of disc space 2 in its relaxed shape. In thisembodiment of the invention, bone graft plunger 820 is straightened toinsert its distal tip 822 into funnel 800 and inserter tube 100, and itassumes its curved or relaxed shape when inserted into disc space 2.

Referring now to FIGS. 72-79, and in accordance with a constructedembodiment of the invention, an extension arm 900 is depicted forsecuring various components of the present system 10 to a plurality ofpedicle screws 9 that are secured to a human spine by known-in-the-artsurgical techniques. With specific reference to FIGS. 72 and 73,extension arm 900 comprises an arm body 902 that engages a centralthreaded rod 910 having a proximal end that may be turned by, forexample, a wrench, nut driver, or like mechanical device. Rod 910 alsoincludes a distal end 914, which is shown in the present embodimenthaving a plurality of helical threads thereon for engaging a pediclescrew having complementary threads therein.

An adjustable clamp 920 is secured to extension arm body 902 by aconventional adjustment knob 921 and concomitant threaded member (notshown). Clamp 920 includes a pair of spaced clamp arms 922 extendingoutwardly from body 902 that are adjustable with respect to one anotherby conventional means, for example a clamp adjustment knob 924 securedto a threaded member 926, that engages complementary threads 928 in eachclamp arm. Extension arm 900 is secured to a complementary pedicle screwby rotating central rod 910 to engage distal end 914 with the pediclescrew. Clamp 920 is then adjusted to position arms 922 to secure, forexample, inserter tube 100 to extension arm 900 in a precise locationfor delivery of inter-body device 20.

FIGS. 74 and 75 depict additional embodiments of extension arm 900 thatinclude an extension arm body 902 that has a distal end 914 having atransverse pin 906 secured thereto for engaging a complementary hook ofa pedicle screw (not shown).

FIGS. 76 and 78 depict an alternative embodiment of extension arm 900having a body 902 that is shaped like an elongated channel, having apair of spaced edges 907 along its length. Distal end 914 includes acut-out portion 916 that engages a head of a pedicle screw 9, as shownin FIG. 78. Clamp 920 is secured to a clamp guide 930 that includes apair of spaced arms 932, each having a groove 934 therein for engagingedges 907 of extension arm 900 body 902. In this embodiment of theinvention, clamp guide 930 arms 932 slide onto body 902 edges 907,thereby providing a clamp guide 930 and claim 920 that is slidable alongthe length of extension arm body 902.

FIGS. 77 and 79 depict a similar extension arm embodiment to those shownin FIGS. 76 and 78, except that distal end 914 includes a vertical pin918 that engages an aperture in pedicle screw 9, as best seen in FIG.79.

FIG. 80 depicts the system 10 of the present invention secured tovertebrae 4 of spine 1 in an exemplary fashion. A plurality of pediclescrews are secured to spine 1 in a conventional fashion, as is known toone of ordinary skill in the art. Extension arm 900 is secured topedicle screw 9 at its distal end 914. Clamp 920 of extension arm 900 ispositioned via clamp guide 930 to engage handle 120 of inserter tube100. Inserter tube 100 is positioned to be inserted through theannulotomy into disc space 2. Finally, trial handle 510 is secured tobullnose 600 and inserted through inserter tube 100.

In operation, the present system 10 and the components thereof may beemployed by a surgeon to effect disc replacement in the followingfashion. Initially, a surgeon makes a longitudinal midline incision inthe area of pathology, through skin, subcutaneous tissue and fascia.Radiologic confirmation of vertebral level is then obtained throughconventional radiographic techniques. Next, the lumbar spine is exposedthrough subperiosteal dissection, extending exposure only to the base ofthe transverse processes to permit identification of the entry pointsfor insertion of pedicle screws 9. If TLIF (transforaminal lumbarinter-body fusion) is planned in conjunction with posterolateral fusion,dissect to the tips of the transverse processes of the levels includedin the fusion. Pedicle screws are then applied in the conventionalmanner, as is known to one of ordinary skill in the art.

Next, a total ipsilateral facetectomy is performed, using an osteotomeor drill. Additional bony removal may be carried out using a KerrisonRongeur or drill to create a bigger space for insertion of appropriatesized implants and instruments. At this point, a surgeon may perform anyadditional neural decompression, if the determination is made that theparticular case requires it. The posterolateral corner of the annulus isexposed maximally to allow an annulotomy as far lateral as possible.Next, a 1 cm-wide annulotomy incision is made.

Once the above-mentioned preparatory steps are completed, a thoroughdiscectomy is performed. It is desirable in one embodiment of thepresent invention to extend the discectomy to the contralateral half ofthe disc space to allow for placement of the longest inter-body device20 possible and to maximize bony surface exposure for fusion to occur.If there is significant disc space 2 collapse, a complete discectomy maynot be possible until disc space 2 distraction is complete.

Next, the surgeon distracts the disc space sequentially withconventional distraction instruments, for example distractors ranging inheight from 6 mm to 16 mm, until a snug fit is achieved. The surgeon maynote the insertion depth and the height of the distractor used since theinsertion depth gauges the depth of disc space 2. The height of thedistractor employed in this step will determine the height chosen forthe box cutter 700, bullnoses 600, inserter tube 100, trial implants400, and inter-body device 20.

Next, the surgeon may apply a conventional contralateral distractor tomaintain disc height and perform any additional discectomy, as necessaryto prepare disc space 2. In one embodiment of the invention, a surgeonmay employ a standard Penfield Elevator to palpate the vertebralendplate and then feel the anterior edge of the vertebral body. Once theanterior edge is felt and the Penfield Elevator dips, then adequatediscectomy up to the anterior annulus has been achieved.

With a known-in-the art nerve root retractor the surgeon next protectsthe exiting and traversing nerve roots. At this point, box cutter 700 isinserted to shave the posterior endplate by utilizing a box cutter headof the same size as the tallest distractor used to achieve a snug fit asdiscussed above. Box cutter head 708 height may be provided on thesurface thereof. It also has markings indicating the distance fromdistal tip 710. The surgeon then decorticates the remaining endplatesurfaces of the superior and inferior vertebral bodies to enhanceformation of bony fusion.

In the next step, the surgeon secures the extension arm 900 loosely tothe inferior pedicle screw 9. Trial handle 510 is next secured to anappropriately sized bullnose 610, with a tapered distal tip 610 and thisassembly is inserted into an identically sized inserter tube 100.Bullnose 600 and inserter tube 100 heights may marked on theinstruments, as necessary.

Next, the assembled bullnose 600 and inserter tube 100 is advanced intodisc space 2 through the annulotomy, by directing inserter tube 100distal end 100 five to ten degrees laterally. The assembly orientationis then slowly manipulated to 0 degrees in the sagittal plane, keepinginserter tube 100 as far lateral in disc space 2 as possible.

Once the above assembly is inserted to the desired depth (as determinedfrom the distractor placement mentioned above, bullnose 600 is removed.The surgeon should note the insertion depth of inserter tube 100 by themarkings on the superior, medial and inferior surfaces thereof toindicate the distance from distal tip 110.

Next, the surgeon assembles handle 510 with the correct sized bullnose600 having a blunt tip 610. Again, bullnose 600 height may be marked onthe surface of the main shaft. Next, bullnose 600 is inserted intoinserter tube 100 by engaging inserter tube handle 120 with trial handle510. In one embodiment of the invention, bullnose 600 having a tapereddistal tip 610 extends 15 mm beyond the inserter tube distal aperture110. Furthermore, bullnose 600 having a blunt distal tip 610 extendsonly 10 mm beyond inserter tube 100 distal tip 110. The surgeon advancesthe handle 510, bullnose 600, and inserter tube 100 assembly deeper intodisc space 2 until bullnose 600 distal end 610 touches the anteriorannulus thereof.

Next, the surgeon secures inserter tube 100 handle 120 to extension arm900 and extension arm 900 distal end 914 is secured tightly to pediclescrew 9. Next, the surgeon can remove bullnose 600, while rememberingthat in this position, there is 10 mm of free space between insertertube 100 distal tip 110 and the anterior annulus of disc space 2, toallow smooth deployment of the bullnose 600 having a blunt distal tip610 and inter-body device 20 into the anterior disc space 2.

In the next step, the surgeon assembles handle 510 to the determinedtrial implant 400 height size. Each trial implant 400 may be marked withits length and height to facilitate assembly in the operating room.Through inserter tube 100, the surgeon next sequentially attempts todeploy three different trial implant 400 lengths (of the chosen trialimplant 400 height), starting with the shortest (for example, 20 mm),then with an intermediate (for example, 25 mm) to the longest (forexample, 30 mm). Saline may be used to lubricate the inserter for easierdeployment.

The longest trial implant 400 length that can be successfully deployedinto disc space 2 determines the inter-body device length to be used.After radiologic confirmation of satisfactory trial implant 400 positionwithin disc space 2, remove trial implant 400 from disc space 2 andinserter tube 100.

In the next step, the surgeon secures handle 510 to the previouslydetermined bullnose 600 height. At this stage, bullnose 600 having bluntdistal end 610 will be employed to push inter-body device 20 throughinserter tube 100. Each inter-body device 20 may be marked with itsheight and length to facilitate assembly. The inter-body device shouldbe visually inspected by the surgeon for any damage. Next, a standardNo. 2 suture 3 may be looped through hitch 50 of inter-body device 20.Suture 3 will allow the inter-body device 20 to be retrieved, ifnecessary, before complete passage through inserter tube 100. Ifinter-body device 20 is retrieved it should again be visually inspectedfor any damage.

The surgeon next fills apertures 46 within the inter-body device 20 cans30 with morselized bone graft material. The relief area 38 between cans30 and anterior wall 40 should not be filled to permit inter-body device20 bridge 60 and cans 30 to flex. Doing so may affect the properdeployment of inter-body device 20 through inserter tube 100 and discspace 2.

Nest, the surgeon inserts inter-body device 20 through inserter tube 100with the concavity of the inter-body device 20 directed medially andhitch 50 directed proximally. Inserter tube 100 medial and lateral sidesmay be labeled on the instrument for ease of insertion. The surgeonpositions looped suture 3 into the suture groove in inserter tube 100handle 120. The groove in inserter tube 100 handle 120 should align withsuture guide groove 612 in bullnose 600. This prevents suture 3 frombeing caught between the sliding surfaces of bullnose 600 and theinterior wall of inserter tube 100.

Using the bullnose 600 handle 510 the surgeon next advances theinter-body device 20 along inserter tube 100 and into anterior discspace 2. Saline may be used to lubricate inserter tube 100 for easierdeployment. Once inserted, the surgeon verifies device 20 position byconventional radiography.

Next, the surgeon pulls looped suture 3 out of hitch 50 and insertertube 100. Inserter tube 100 is next unlocked from extension arm 900 andhandle 510, and bullnose 600 and inserter tube 100 assembly is withdrawnfrom disc space by approximately 10 mm in preparation for application ofbone graft material. A slap hammer may be used to aid withdrawal. Thisassembly is then secured back to extension arm 900 utilizing clamp 920.

Next, the surgeon disengages handle 510 from inserter tube 100 handle120 and pulls bullnose 600 out of inserter tube 100. Bone graft funnel800 is then placed on the proximal end of inserter tube 100 handle 120.The surgeon then assembles the appropriate size bone graft plunger 820tip 822 to handle 510. In one embodiment of the invention, each plungertip 822 is marked with its height. Next, the surgeon deposits morselizedbone graft material 7 into bone graft funnel 800, and pushes it downinserter tube 100 using the bone graft plunger 820. Once this step iscompleted, the bone graft funnel 800 is disconnected from inserter tubehandle 120. The bone graft material 7 may then be pushed further intodisc space 2 using bone graft plunger 820 again.

Finally, the surgeon may remove the bone graft plunger 820, disconnectextension arm 900 from pedicle screw 9, and remove extension arm 900 andinserter tube 100 as an assembled unit to complete the procedure.

While the present invention has been shown and described herein in whatare considered to be the preferred embodiments thereof, illustrating theresults and advantages over the prior art obtained through the presentinvention, the invention is not limited to those specific embodiments.Thus, the forms of the invention shown and described herein are to betaken as illustrative only and other embodiments may be selected withoutdeparting from the scope of the present invention, as set forth in theclaims appended hereto.

1. (canceled)
 2. An interbody device, comprising: a first can; a secondcan; a flexible bridge that extends between the first and second cans toconnect the first and second cans together; and a relief area definedbetween the first can, the second can, and the flexible bridge, therelief area configured to enable at least one of the first and secondcans to move relative to the flexible bridge.
 3. The interbody device ofclaim 2, wherein the first and second cans are configured to flex inwardtoward the flexible bridge to converge with the flexible bridge anddecrease a size of the relief area.
 4. The interbody device of claim 2,wherein at least one of the first and second cans defines an innersurface that extends along a portion of the flexible bridge and isdisposed in spaced-apart relation with the flexible bridge, the innersurface disposed adjacent to the flexible bridge and defining at least aportion of the relief area.
 5. The interbody device of claim 4, whereinthe inner surface is arcuate.
 6. The interbody device of claim 2,wherein the flexible bridge includes polymeric material.
 7. Theinterbody device of claim 5, wherein at least one of the first andsecond cans includes metal.
 8. The interbody device of claim 2, whereinat least one of the first and second cans includes corrugated ridgesthat are configured to frictionally engage spinal bone.
 9. The interbodydevice of claim 2, wherein the first can includes a hitch.
 10. Theinterbody device of claim 9, wherein the hitch supports a pin.
 11. Theinterbody device of claim 2, wherein at least one of the first andsecond cans defines an aperture positioned to facilitate spinal fusionand configured to receive bone graft.
 12. The interbody device of claim11, wherein the aperture is non-circular.
 13. The interbody device ofclaim 12, wherein the aperture is curvilinear.
 14. The interbody deviceof 2, wherein the first and second cans are independently movablerelative to one another.
 15. The interbody device of claim 2, whereinthe flexible bridge is configured to urge the first and second canstoward an unflexed state upon being urged into a flexed state.
 16. Aninterbody device, comprising: a first can including a first material; asecond can; a bridge that extends between the first and second cans toconnect the first and second cans together, the bridge including asecond material that is different from the first material; and a reliefarea defined between the first can, the second can, and the bridge, therelief area configured to enable the first and second cans to convergetoward the bridge.
 17. The interbody device of claim 16, wherein atleast one of the first and second cans defines an inner surface thatextends along a portion of the bridge and is disposed in spaced-apartrelation with the bridge, the inner surface disposed adjacent to thebridge and defining at least a portion of the relief area.
 18. Theinterbody device of claim 17, wherein the inner surface is arcuate. 19.The interbody device of claim 16, wherein the first material includespolymeric material.
 20. The interbody device of claim 16, wherein thesecond material includes metal.
 21. The interbody device of claim 16,wherein at least one of the first and second cans includes corrugatedridges that are configured to frictionally engage spinal bone.
 22. Theinterbody device of claim 16, wherein the first can includes a hitch.